Casualty flashback: Fatal sinking of the tanker Bow Mariner

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The 570-foot Singapore-flagged chemical and oil tanker Bow Mariner sank 15 years ago when the ship caught fire and sustained two explosions, resulting in the deaths of 21 of 27 crewmembers 45 miles off the coast of Virginia on Feb. 28, 2004.  

The vessel was transporting over 3 million gallons of ethyl alcohol on a voyage from New York to Texas. It had previously carried methyl tert-butyl ether (MTBE) in its other 22 cargo tanks that were discharged in New York.

The cause of the explosion was the flammable fuel and air mixture created during the cleaning of residual MTBE from Bow Mariner’s cargo tanks. The cargo holds were ordered to be cleaned via the opening of the cargo accesses. This allowed residual MTBE vapors to escape the holds during the cleaning process. 

The source of ignition remains unconfirmed, but once the flammable vapors were released from the cargo holds, the likelihood of a fire igniting was significantly increased. This tragic incident helped bring forward numerous marine safety improvement impacts and lessons learned.

The formal Coast Guard investigation report, conducted by Coast Guard Marine Safety Office Hampton Roads on behalf of the government of Singapore, highlighted a number of contributing factors, including the failure to properly fully implement the vessel's safety, quality and environmental protection management system (SQEMS). A safety management program is required to be implemented by the vessel and its managing company as outlined in the International Safety Management Code. The vessel’s SQEMS plan called for using inert gas during the discharge of MTBE, which was not followed.

Bow Mariner was not required to carry immersion suits due to its lifeboats being fully enclosed. Regulations have since changed, and a comparable vessel today is now required to carry immersion suits. Immersion suits are designed to help increase survival chances in cold water. Had Bow Mariner carried immersion suits and its crew had the opportunity to don these suits, the survival rate could have been much higher.

The Coast Guard investigation discovered evidence that regular and effective emergency crew drills were not conducted on board Bow Mariner. The ship's general alarm was never sounded nor was an announcement made to alert or direct the crew. Current regulations require ships to conduct a fire drill and abandon-ship drill monthly.

The loss of Bow Mariner is considered one of the worst chemical tanker disasters in history and is a tragic reminder of the consequences resulting from unsafe chemical cargo handling practices.

“It is the Coast Guard's mission to prevent similar accidents from happening; ensure the safety of life at sea for mariners, and protect the marine environment,” said Capt. Kevin Carroll, commanding officer of Coast Guard Sector Hampton Roads. “Coast Guard marine inspectors are trained to identify flaws in safety management and evaluate emergency drill performance.”  

By Professional Mariner Staff